Evaluation on toughness degradation of Cr–Mo–V steel using miniaturized impact specimen technology

Miniaturized specimen technology is inevitable when the amount of available material for test is limited. In this study, miniaturized Charpy V-notched specimens of 1Cr–1Mo–0.25 V rotor steel with five different aging periods were artificially prepared by an isothermal aging heat treatment at 630°C and tested. For the miniaturized specimens, two different types of specimens with or without side groove were utilized. A correlation between the ductile brittle transition temperature (DBTT) obtained by the miniaturized specimen and that by the standard specimen was investigated. In addition, the relationship between fracture toughness and DBTT by the miniaturized specimen of degraded 1Cr–1Mo–0.25 V rotor steels was proposed.